1. Field of the Invention
This invention relates to fresh air ventilator systems for conditioning the air that is circulated within a building. More particularly, this invention relates to an air conditioning system for use in a building such as an educational plant, that requires a minimum amount of fresh air to be circulated when the building is occupied; in addition to the usual heating and cooling requirements for comfort.
2. Description of the Prior Art
The field of air conditioners for conditioning air to be circulated in buildings has been highly developed and the prior art has seen a wide variety of systems for this purpose. In certain types of buildings, such as educational plants, the requirements have been more stringent; frequently imposed by statute. For example, a minimum amount of fresh air is required to be circulated in the building to minimize the chance of accumulation of stale air or constitutents thereof that tend to cause inhalation difficulties, spread contagious diseases or incur an accident. Of the numerous prior art patents, the closest apparatus and system of which I am aware is disclosed in U.S. Pat. No. 3,831,395. In that patent, there is disclosed a unit for setting in a classroom or the like to obviate the therein delineated and implied disadvantages of the earlier art. Specifically, the earlier art had required altering the building; difficulty and loss of classroom time in installation and maintenance; the distraction and discomfort by operating noises; and the requirements of undue floor space necessarily withdrawn from teaching use. While the apparatus described in U.S. Pat. No. 3,831,395 was useful in minimizing some of the disadvantages, it still required installation adjacent an outside wall, occupying a portion of the classroom space; was visible from the classroom; and, though its noise level was low, could still be heard in the classroom. Because it required an outside wall, that apparatus was frequently emplaced over a window or the like; blocked out a portion of the view of the exterior; and interfered with the design of the architect.
In short, experience with the prior art has indicated that a most nearly ideal fresh air ventilator system would have the following features that have not been heretofore available in the prior art.
1. The ventilator unit should be disposed exteriorly of the building, such as exteriorly of the classroom, so as to avoid taking up valuable classroom floor space, eliminate noise in the room and give a better atmosphere for learning or working.
2. The ventilator unit should be in a weatherproof enclosure and should engage the building by a suitable sealing means that obviates difficulties with water coming in around ducts, plenums and the like.
3. The ventilator unit should have fresh air inlets that enable obtaining fresh air for circulation within the building without getting precipitation into the circulation system and without unsightly protuberances, hoods and the like that interfere with blending into a pleasing architectural scheme even when visible from outside the building. 4. The ventilator unit should have a proportioning damper means on the return air to form a part of the channel that comprises part of the exhaust means for exhausting stale air.
5. The ventilator system should conserve power; particularly in the cooling operation by utilizing fully the ambient cooling available. In doing so, the system should alleviate problems with changing the pressure inside the building, as by inlet or discharge blowers that have excess power that raise or lower the pressure in the building and that require more energy for operation than is necessary.